8-Aryloctanoic acids of a general formula I, having the 2S,4S,5S,7S-configuration
especially compound such as Aliskiren, wherein R1 represents CH3OCH2CH2CH2—, R2 and R4 hydrogen and R5—NHCH2C(CH3)2CONH2, (INN name: 5-amino-N-(2-carbamoyl-2-methylpropyl)-4-hydroxy-2-isopropyl-7-[4-methoxy-3-(3-methoxypropoxy)benzyl]-8-methyl-nanoamide), are excellent new antihypertensive which interfere with the rennin-angiotensin system.
After discovery of the biological activity of compounds of general formula I in 1994, first synthesis of Aliskiren has been also disclosed (U.S. Pat. No. 5,559,111 and EP 0 678 503). Since Aliskiren contains 4 chiral centers, synthesis of enantiomerically pure compound is very complex: After 2001 many patents and publications have been filed or published claiming alternative routes to Aliskiren (WO 01/09083, WO 01/09079, EP 1 215 201, WO 02/02508, WO 02/02500, WO 02/02487, WO 02/08172, WO 02/092828, WO 02/02500, WO 03/103653, UK 2 431 640, GB 2 431 641, GB 2 431 642, GB 2 431 643, GB 2 431 644, GB 2 431 645, GB 2 431 646, GB 2 431 647, GB 2 431 48, GB 2 431 649, GB 2 431 650, GB 2 431 651, GB 2 431 652, GB 2 431 653, GB 2 431 654, WO 2005/054177, WO 2005/090305, WO 2005/ 051895, WO 2006/131304, WO2006/095020, WO2006/024501, WO2007/054254, WO2007/039183, EP 2 062 874, EP 1958 666, WO 2007/006532, WO2007/045420, WO2008/155338, WO2008/119804, CA 2 634 513, WO2007/048620, WO2007/118681, EP2189442, US2009/0076062, WO2009/049837, WO2010/010165, Tetrahedron Letters 2000, 41, 10085, ibid. 2000, 41, 10091, ibid. 2001, 42, 4819, Drugs Fut. 2001, 1139, J. Org. Chem. 2002, 67, 4261, Helv. Chim Acta 2003, 86, 2848, Tetrahedron Letters 2005, 46, 6337, J. Org. Chem. 2006, 71, 4766, Organic Process & Develop 2007, 11, 584, Tetrahedron Letters 2008, 49, 5980 and Org. Lett. 2010, 12, 1816). Nevertheless, none of them fulfill requirements for a short and cost effective manufacturing process.